#include <REGX52.H>
#include "delay.h"

unsigned char Key()
{
	unsigned char KeyNumber = 0;
	
	if(P3_1 == 0){Delay100us(20); while(P3_1==0); Delay100us(20); KeyNumber = 1;}
	if(P3_0 == 0){Delay100us(20); while(P3_0==0); Delay100us(20); KeyNumber = 2;}
	if(P3_2 == 0){Delay100us(20); while(P3_2==0); Delay100us(20); KeyNumber = 3;}
	if(P3_3 == 0){Delay100us(20); while(P3_3==0); Delay100us(20); KeyNumber = 4;}
	return KeyNumber;
}